RISHI Sunak embarked on a blink-and-you’ll-miss-it visit to Scotland last week. I think we’re a fairly friendly bunch, but for some reason UK prime ministers treat trips up north as an obligation to be resentfully fulfilled: like a tax return, or a visit to see a difficult relative.

Still, credit where it is due – he came: which is more than can be said for his predecessor Liz Truss.

He was here to announce two new freeports in Scotland and he made it clear he didn’t want to answer questions on anything else.

Enter, STV’s formidable political editor Colin Mackay. King Colin regularly makes mincemeat of politicians of all stripes, particularly when they commit the cardinal sin of not answering the question he has asked them.

In a clip that has been shared widely, Colin Mackay asked the Prime Minister about the SNP’s plan to use the next UK General Election as a de facto referendum on independence.

He wanted to know if Sunak would respect the result of a de facto referendum, if he was still Prime Minister after the next election. It’s a simple question with only two possible one-word answers.

Yet isn’t it always these most basic of questions that seem to befuddle slippery politicians?

“I’ll tell you what I’m focused on and that’s delivering for people in Scotland,’’ replied Sunak, in a valiant attempt at a deflection.

But Mackay wasn’t having it and told the Prime Minister as much.

On and on it went, question – soundbite, question – increasing exasperation.

“You’re completely ignoring my question which is about the possibility of the next general election being a de facto referendum – would you respect the outcome of that?’’

Answer, there came none. There was a glorious moment during the exchange when Sunak once again tried to divert from the question with the politician’s go-to line “What I’m focused on … ’’

And Mackay, sounding like a weary dad who is sick of explaining the same thing over and over again, shoots back with: “I’m not asking what you’re focused on, I’m asking you to focus on this!’’

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It was a short interview, but a very telling one. The SNP’s de facto referendum plan is a headache for Unionist politicians who haven’t had time to think through what their strategy will be if it comes to pass.

A de facto referendum is, by its very nature, a high-risk option for the SNP. Where the 2014 referendum was ordered and meticulously planned, this is a far more chaotic route to giving the people of Scotland a chance to have their say on Scotland’s future.

This isn’t a criticism of the First Minister’s gamble, I understand why she has suggested it as a way forward. There aren’t many options available to her given continuing Westminster intransigence and the recent Supreme Court ruling.

Sixteen- and 17-year-olds overwhelmingly back independence for Scotland but in a general election they won’t get the chance to express it and we will lose that chunk of support. The SNP will be hoping that the high-stakes nature of their offering will be enough to motivate those Yes supporters who haven’t voted in the last few general elections back to the ballot box.

The undeniable risks that the SNP face from a de facto referendum also make the Unionist position more difficult. Unionist parties in Scotland have only two options for responding to the plan. They can completely ignore the SNP’s proposal and fight the next General Election on the basis that it is an ordinary vote. This would be particularly tricky for the Scottish Tories, who – despite their insistence that they are sick of talking about the constitution – have based all their election campaigns since 2014 on the premise that a vote for them is a vote to “Say No to indyref2’’.

The other option is for Unionist parties to tell the SNP to bring it on. This would be a gamble, but it is one they might be willing to take, given that independence-supporting parties securing over 50% of the vote is a pretty tall order.

The SNP will hold a special conference in late March to allow members to have their say on the de facto referendum plan and how it would work in practice. It is set to be a fiery affair, given the conflicting views within the party on the best way forward. A proper, messy, heated debate is long overdue.

For the last few years, impatience within the wider independence movement has been replaced by a feeling of frustration.

This is a chance to rejuvenate the debate and move on from the tired back-and-forth about process.

A de facto referendum is a high-risk gamble that might not pay off. But if the alternative is sitting around waiting for the UK Government to respect democracy then it is a gamble worth taking.

We shouldn’t let the perfect be the enemy of the good.